Polynomials and fractions

9000039302

Level: 
B
Find \(N\), the number of the turns, as a function of the other variables in the formula for the magnetic induction of a solenoid. \[ B =\mu \frac{NI} {l} \]
\(N = \frac{Bl} {\mu I} \)
\(N = \frac{Bl\mu } {I} \)
\(N = B -\mu \frac{I} {l} \)
\(N = \frac{Bl} {\mu } - I\)

9000039304

Level: 
B
Find the focus length \(f\) as a function of the other variables from the following equation relating this distance with object and image distances \(a\) and \(a'\). \[ \frac{1} {f} = \frac{1} {a} + \frac{1} {a'} \]
\(f = \frac{aa'} {a+a'}\)
\(f = \frac{a-a'} {a+a'}\)
\(f = a + a'\)
\(f = \frac{a} {a'}\)

9000039305

Level: 
B
Find \(m_{1}\) as a function of the other variables from the following mixing equation. \[ w_{1}m_{1} + w_{2}m_{2} = w_{3}m_{3} \]
\(m_{1} = \frac{w_{3}m_{3}-w_{2}m_{2}} {w_{1}} \)
\(m_{1} = \frac{w_{3}m_{3}w_{2}m_{2}} {w_{1}} \)
\(m_{1} = \frac{w_{3}m_{3}+w_{2}m_{2}} {w_{1}} \)
\(m_{1} = \frac{w_{2}m_{2}-w_{3}m_{3}} {w_{1}} \)